The name 'Mundburg' is etymologically identical to Elvish Minas Tirith, with both meaning essentially 'Tower of Guard'. It seems, then, that the name 'Mundburg' originated as a translation of Minas Tirith into the language of the Northmen, and so its use must reflect the change of name from Minas Anor in about III 2002. The Northmen presumably had an earlier name, too, and indeed a remnant of this is apparently preserved in 'Sunlending', their name for Anórien where the Mundburg stood. They might, therefore, have historically referred to Minas Anor as the 'Sunburg' or something similar, but if so, no record of this earlier name exists.